There is a similar topic to this one located at: viewtopic.php?t=12417But it is a little outdated and I find my approach a little bit easier..

Introduction

A realtime kernel enables realtime preemption for the kernel which enhances the performance of multimedia applications greatly. A realtime kernel is recommended for small music studios, for people who want to live record MIDI keyboards or for people who want to get overall better performance from their PC. So you want to build your own realtime kernel? Fine, now let's get started!

1. Preparations

If you are familiar with the Terminal and you know how to compile programs, then you are ready to build a realtime kernel. Before we start, I would like to add that you need to run all the commands mentioned in this post as root. Ok, let's do some preparations before the actual kernel building:

You can easily load the configuration files from xconfig by choosing File -> Load from the menu. If you use menuconfig, then you need to scroll down and choose "Load an Alternate Configuration File".. But remember to save your configuration before building the kernel!

If you are ready and you have saved your configuration, let's build the kernel!

3. Building the kernel

Building the kernel is a fairly easy process, but may take very long depending on your PC's specifications and how the kernel was configured.Also note that with even a little misconfiguration, you can make a bad kernel.Despite the consequences of what can happen, let's build the kernel:

I have some good news (and a bad one too).. but good first:
Now that Linux 2.6.21is out, I tried to build that using my procedure and it worked fine, so when I update this one, I will make the links point to 2.6.21 instead.

And the bad news:
I have tried more than 20 free hosting providers, but none of them did either accept the format of the configs, or their uptime was just as bad as that ASPHost one.. Hopefully I am going to find a good host